Working With Rails

You can use this:
User.all(:order => “id DESC”, :limit => 5)
And same on your other models.

I would do it like that:
a = []
a << User.find(:first, :order =>”created_at DESC”)
a << Investment.find(:first, :order =>”created_at DESC”)
a << Comment.find(:first, :order =>”created_at DESC”)
a..sort {|a,b| a.created_at <=> b.created_at}.first

Thanks guys for ur help….....

If you just the last entry in the table, you can use this:

User.last
Investment.last
Comment.last

Though User.last will work in most of the scenarios, but if you have any default_scope on your AR::Base, it will be considered while fetching the last record. Say if you have:

class User < ActiveRecord::Base
  default_scope :order => "login DESC" 
end

User.last will return last user sorted by login.